BloombergLP::bslstl::Variant_OverloadHelper<t_SRC, bsl::variant<t_HEAD, t_TAIL...>, bsl::void_t<decltype(Variant_OverloadSetImp<t_SRC, 0, t_HEAD, t_TAIL...>:: candidate(std::declval<t_SRC>()))>>

Provide Index when a unique best-match alternative is found.

Synopsis

Declared in <bslstl_variant.h>

template<
    class t_SRC,
    class t_HEAD,
    class... t_TAIL>
struct Variant_OverloadHelper<t_SRC, bsl::variant<t_HEAD, t_TAIL...>, bsl::void_t<decltype(Variant_OverloadSetImp<t_SRC, 0, t_HEAD, t_TAIL...>::
                             candidate(std::declval<t_SRC>()))>>;

Description

This partial specialization is used when a "unique" best match is found for converting std::declval<t_SRC>() to one of (template parameters) t_HEAD, t_TAIL....

Type Aliases

NameDescription
Index Index constant equal to the index of the alternative selected by overload resolution among the candidate functions.